Mobafire is actually a great place to start if you need a general idea for a build. Just make sure to keep track of what does and doesn't work for you and adjust your items accordingly. I find that the best thing is to go to different sites like Mobafire, Solomid, etc and look at the top ranked guides. Then see what items they have in common which should give you a pretty good idea of how to build your champ.
Too bad that build is pretty close to being "standard"...I don't get why people bash this site when most of it is very close to solomid and other guides.
The only bad thing about the guide is that is suggests going Dorans as your first item. TC, NEVER go for Dorans anything as your first item.
Start: Boots and 3 Health pots Early game: Berserker greaves, 2 dorans blades, vampiric scepter Mid late core items: Infinity edge or bloodthirster, Phantom dancers Later: Last whisper, QSS, other stuff
I play a ton of graves, I found my favorite build to be: boots potsx3 greaves Either: BF sword if you can afford that with your greaves and you're ahead in lane, 2 dorans if you're behind in lane, and 1 dorans 1 vampiric sceptre if you're even Next go Bloodthirster -> IE -> PD -> LW -> whatever, it's your choice. I don't go for defensive items and I'll build a second bloodthirster and 2nd phantom dancer as well, but I know many people like to use QSS or GA so you could do that instead of the second BT